Defender Defender is a GPS/GSM based motion sensor security system that provides: pinpoint tracking accuracy, automated responsive alert notifications, unparalleled service levels and the best customer controls on the market. Our proactive system will activate and alert the user the moment any disturbance is detected in the vehicle. Movements without the key in the ignition, forced entry through doors or windows, or if your vehicle leaves a predetermined geo-zone, will all trigger the device.